Coronal Holes

Astronomy and Astrophysics – Astrophysics – Solar and Stellar Astrophysics

Scientific paper

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

61 pages, 12 figures. Accepted by the online journal "Living Reviews in Solar Physics." The abstract has been abbreviated slig

Scientific paper

Coronal holes are the darkest and least active regions of the Sun, as observed both on the solar disk and above the solar limb. Coronal holes are associated with rapidly expanding open magnetic fields and the acceleration of the high-speed solar wind. This paper reviews measurements of the plasma properties in coronal holes and how these measurements are used to reveal details about the physical processes that heat the solar corona and accelerate the solar wind. It is still unknown to what extent the solar wind is fed by flux tubes that remain open (and are energized by footpoint-driven wave-like fluctuations), and to what extent much of the mass and energy is input intermittently from closed loops into the open-field regions. Evidence for both paradigms is summarized in this paper. Special emphasis is also given to spectroscopic and coronagraphic measurements that allow the highly dynamic non-equilibrium evolution of the plasma to be followed as the asymptotic conditions in interplanetary space are established in the extended corona. For example, the importance of kinetic plasma physics and turbulence in coronal holes has been affirmed by surprising measurements from UVCS that heavy ions are heated to hundreds of times the temperatures of protons and electrons. These observations point to specific kinds of collisionless Alfven wave damping (i.e., ion cyclotron resonance), but complete models do not yet exist. Despite our incomplete knowledge of the complex multi-scale plasma physics, however, much progress has been made toward the goal of understanding the mechanisms responsible for producing the observed properties of coronal holes.

No associations

LandOfFree

Say what you really think

Search LandOfFree.com for scientists and scientific papers. Rate them and share your experience with other people.

Rating

Coronal Holes does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Coronal Holes, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Coronal Holes will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFWR-SCP-O-556304

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.